Determination of the half-life of ${}^{37}\mathrm{Ar}$ by mass spectrometry

The half-life of ${}^{37}\mathrm{Ar}$ has been determined via mass spectrometry by measuring the ratio of ${}^{37}\mathrm{Ar}$ to stable ${}^{36}\mathrm{Ar}$ as a function of time in neutron-irradiated samples of ${\mathrm{CaF}}_2.$ The half-life we obtain is $34.95\pm 0.08\mathrm{d}$ (95% confidence level). This result is compared to previous experiments based on radioactivity measurements.